A generic boost pressure control system is known from DE 199 65 420 A1, which describes a method for boost pressure control in an internal combustion engine using a boost pressure control device, by means of which from the control deviation between a setpoint boost pressure and an actual boost pressure a manipulated variable is generated which has a D [differential] portion supplied by a differential control unit, the D portion being adapted as a function of a control deviation of a transient effect detected and evaluated for a predetermined evaluation time period. In this specific case, the output variable from the controller is reduced for an adjustment unit for the turbine blade as a function of the rate of control deviation between the boost pressure actual value and the boost pressure setpoint value; i.e., when the boost pressure actual value approaches the boost pressure setpoint value during acceleration, the adjustment variable for actuation of the adjustment unit for the turbine blades is reduced, specifically, at a rate that is greater the more rapid the boost pressure buildup.
In addition, from DE 197 12 861 A1 and DE 195 02 150 C1 it is known to specify a correction value for an integral portion of an integral action controller, the aim being to allow robust control of the supercharging of an internal combustion engine, in particular for cases in which extremely variable interfering parameters, such as greatly variable boost pressure setpoint values at full load, occur, or for extremely variable rotational speed dynamics.
Due to serial dispersion dictated by the manufacturing process, for example in the vicinity of a boost pressure control valve, such as in the vicinity of a spring-loaded pressure box which acts on a bypass valve, for some vehicles a different control characteristic is obtained which is undesirable. The same also applies to aging symptoms of components in the vicinity of the boost pressure control valve, which likewise may vary from vehicle to vehicle.
The object of the present invention, therefore, is to provide a method for controlling boost pressure in an internal combustion engine by means of which the aforementioned problems regarding serial dispersion and aging symptoms of the components of a controlled system, in particular for a boost pressure control valve, are avoided, and a high-quality and reproducible control may be provided with the lowest possible control deviation between the setpoint boost pressure and the actual boost pressure, as well as the best possible performance of the boost pressure buildup.